We consider the problem of distributing timesensitive
information from a collection of sources to mobile
users traversing a wireless mesh network. Our strategy is to
distributively select a set of well-placed nodes (warehouses) to act
as intermediaries between the information sources and clusters
of users. Warehouses are selected via the distributed construction
of Hierarchical Well-Separated Trees (HSTs), which are sparse
structures that induce a natural spatial clustering of the network.
Unlike many traditional multicast protocols, our approach is
not data driven. Rather, it is agnostic to the number and position
of sources as well as to the mobility patterns of users. Whereas
source-rooted tree multicast algorithms construct a separate routing
infrastructure to support each source, our sparse and flexible
infrastructure is precomputed and efficiently reused by sources
and users, its cost amortized over time. Moreover, the route
acquisition delay inherent in on-demand wireless ad hoc network
protocols is avoided by exploiting the HST addressing scheme.
Our algorithm ensures with high probability a guaranteed stretch
bound for the information delivery path, and is robust to lossy
links and node failure by providing alternative HST-induced
routes. Nearby users are clustered and their requests aggregated,
further reducing communication overhead.